Fabrication of a vertically aligned carbon nanotube electrode and its modification by nanostructured MnO2 for supercapacitors

2009 ◽  
Vol 81 (12) ◽  
pp. 2317-2325 ◽  
Author(s):  
Wei-De Zhang ◽  
Jin Chen

Strongly bonded arrays of vertically aligned, multi-walled carbon nanotubes (MWNTs) have been successfully grown on Ta foils, and provide a convenient basis for fabricating electrodes with high conductivity and stability. The MWNT arrays were further coated by nanostructured MnO2 through reacting with KMnO4 solution at room temperature. The morphology of the MnO2/MWNT nanocomposite was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the MnO2 is a beehive-like nanostructure that is homogeneously and densely coated on the surface of the MWNTs. The capacitance of the MWNT electrode was significantly increased from 0.14 to 6.81 mF cm–2 after being modified with nanostructured MnO2, that is, the mass-specific capacitance of the bare and MnO2-modified MWNTs was about 33 and 446 F g–1, respectively. The MnO2/MWNT nanocomposite on Ta foils could be potential for developing a supercapacitor.

2008 ◽  
Vol 607 ◽  
pp. 183-185
Author(s):  
Wei Zhou ◽  
Shao Jie Yue ◽  
Jun Jun Wang ◽  
Bo Wang ◽  
Ya Ping Zheng

Epoxy nanocomposites with multi-walled carbon nanotubes (MWNTs) were prepared. The interaction between MWNTs and epoxy matrix and microstructure were systematically investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and the positron annihilation technology (PAT) respectively. The glass transition temperatures were determined by the variation of the free volume size.


2013 ◽  
Vol 669 ◽  
pp. 55-62 ◽  
Author(s):  
Yi Na Xiong ◽  
Xiao Hua Chen ◽  
Qun Huang ◽  
Long Shan Xu

Polypropylene (PP)-coated multi-walled carbon nanotubes (MWNTs) composite with MWNTs exceptional alignment dispersed and improved mechanical properties was prepared with maleic anhydride (MAH) as a compatibilizer and poly (butyl methacrylate) (PBMA) as a binding. Scanning electron microscopy (SEM) results showed that MWNTs within composite were aligned without aggregation and the oriented MWNTs were connected by matrix. High-resolution transmission electron microscopy (HRTEM) results demonstrated that the nanotubes were densely coated with a PP layer. Infrared spectroscopy (IR) results revealed that there was covalently linkage of MWNTs with PP via MAH. The interactions between MWNTs-PP and MWNTs-PBMA induced orientation of MWNTs. The improved mechanical properties of PP - coated MWNTs composite was also shown.


2017 ◽  
Vol 54 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Maria Adina Vulcan ◽  
Celina Damian ◽  
Paul Octavian Stanescu ◽  
Eugeniu Vasile ◽  
Razvan Petre ◽  
...  

This paper deals with the synthesis of polyurea and its use as polymer matrix for nanocomposites reinforced with multi-walled carbon nanotubes (MWCNT). Two types of materials were obtained during this research, the first cathegory uses the polyurea as matrix and the second one uses a mixture between epoxy resin and polyurea. The nanocomposites were characterized by Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM) and Tensile Tests .The elastomeric features of nanocomposites were highlighted by the results which showed low value of Tg. Also higher thermal stability with ~40oC compared with commercial products (M20) were observed, but lower mechanical properties compared to neat polyurea.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Shuang-Xi Xue ◽  
Qin-Tao Li ◽  
Xian-Rui Zhao ◽  
Qin-Yi Shi ◽  
Zhi-Gang Li ◽  
...  

Multi-walled carbon nanotubes (MWCNTs) were irradiated by 1.2 keV Ar ion beams for 15–60 min at room temperature with current density of 60 µA/cm2. The morphology and microstructure are investigated by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that carbon nanofibers are achieved after 60 min ion irradiation and the formation of carbon nanofibers proceeds through four periods, carbon nanotubes—amorphous carbon nanowires—carbon nanoparticles along the tube axis—conical protrusions on the nanoparticles surface—carbon nanofibers from the conical protrusions.


Fibers ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 31 ◽  
Author(s):  
Renata Fortini ◽  
Asmus Meyer-Plath ◽  
Dominic Kehren ◽  
Ulrich Gernert ◽  
Leonardo Agudo Jácome ◽  
...  

In this work the flexural rigidity of individual large diameter multi-walled carbon nanotubes (MWCNTs) was investigated. The bending modulus were obtained by detecting the resonance frequencies of mechanically excited cantilevered carbon nanotubes using the so-called dynamic scanning electron microscopy technique, and applying the Euler–Bernoulli beam theory. For the nanotubes studied, we determined a modulus of up to 160 GPa. This agrees with values reported by other authors for MWCNTs produced by catalytic chemical vapor deposition, however, it is 6-8 times smaller than values reported for single and multi-walled carbon nanotubes produced by arc-discharge synthesis. Toxicological studies with carbon nanotubes have been showing that inhaled airborne nanofibers that reach the deep airways of the respiratory system may lead to serious, asbestos-like lung diseases. These studies suggested that their toxicity critically depends on the fiber flexural rigidity, with high rigidity causing cell lesions. To complement the correlation between observed toxicological effects and fiber rigidities, reliable and routinely applicable measurement techniques for the flexural rigidity of nanofibers are required.


2013 ◽  
Vol 750-752 ◽  
pp. 336-339
Author(s):  
Fa Chao Wu ◽  
Teng Fei Shen

In this work, CaCO3 nanoparticles have been synthesized via heat-treatment of a new precursor. Effect of calcinations temperature on particle size has been investigated. The products were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). nanoCaCO3 was modified using chloroform as solvent and fatty acid as modifier atroom temperature. The advantage of this modification is that it can be proceed at room temperature and it can reduce energy consumption.


Author(s):  
Kei Ishikawa ◽  
Hai Duong ◽  
Junichiro Shiomi ◽  
Shigeo Maruyama

Evaporation of different metals (Au, Ti, Al and Pd) onto Vertically-Aligned Single-Walled Carbon Nanotubes (VASWNT) has been studied. Observations through Scanning Electron Microscopy (SEM) showed a clear metal-dependence of the deposition layer structure on top of the VASWNT, reflecting the variation of wettability and cohesive energy of each metal. These characteristics also influence the structures of the metal penetrated through the top surface into VASWNT film, where metal forms particles inside VASWNT film except for Ti. A simple annealing technique to remove metals penetrated in the SWNT films is demonstrated. Some peculiar morphologies found during the processes are also presented.


2012 ◽  
Vol 602-604 ◽  
pp. 183-186 ◽  
Author(s):  
Jing Liu ◽  
Rong Wu ◽  
Jin Li ◽  
Yan Fei Sun ◽  
Ji Kang Jian

In this paper, we report the synthesis of cubic silicon carbide (3C-SiC) nanoparticles by direction reaction of silicon powders and carbon nanotubes. The as-prepared SiC nanoparticles were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and Raman scattering at room temperature. The possible growth mechanism is proposed.


2012 ◽  
Vol 454 ◽  
pp. 63-66
Author(s):  
Xia Yuan ◽  
Yu Liang An ◽  
Chen Zhang ◽  
Hong Chao Sui

Single-walled carbon nanotubes (SWNTs) have been successfully prepared from starch by arc discharge technique. The SWNTs products were characterized by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The growth mechanism of the SWNTs was discussed in terms of the starch. The results demonstrate that starch is one of the suitable precursor for making SWNTs by arc discharge method.


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